The bin blender, or tote blender as it is also called, is one of a family of devices for batch mixing particulate solids, in which mixing is promoted by rotating a vessel containing the solids about a fixed axis. Bin blenders usually have a square cross-section, constant in the upper part of the bin, and reducing uniformly to a discharge point at the lower end. The axis of rotation is fixed at an angle of typically about 15 degrees to a diagonal drawn between opposite corners of a cross-section through the bin. Bin blenders are an attractive option for many processes, because the blending vessel can also be used for storing and transporting the particles, while keeping them in a controlled environment.
The purpose of a blender is to produce a uniform mixture of two or more different components, which are placed in the blender in fixed proportions to each other, so that, after the blender has been operated, samples taken from the mixture contain the different components in proportions the same as or similar to the proportions of the components placed in the blender. In many industrial applications, the mixture made in the blender is removed from the blender, and then divided into batches. If the components in the blender are not intimately and uniformly mixed, then the proportions of the components in the different batches can differ from batch to batch. Also, the proportions of the components in a batch can differ from the proportions of the components placed in the blender. For most mixing operations, if the proportions of the components in samples taken from the mixture are sufficiently close to the proportions of the components placed in the blender, then the mixing operation is thought of as satisfactory. The extent to which the proportions of the components must be similar to the proportions of the components placed in the blender, or the limits of the composition of the mixture are often given in specifications relating to the particular mixture and mixing operation.